在氢气保护下将MoSi2/Mo涂层加热至1000℃,再迅速冷却至室温进行热震循环,表征了材料在热震循环过程中裂纹的演变过程并评估了MoSi2/Mo涂层的热冲击行为.采用Abaqus软件计算了MoSi2/Mo涂层在热冲击过程中的应力分布,讨论了热震循环中裂纹的发展过程.结果 表明:Mo基体与MoSi2涂层之间存在较高的热冲击应力,这将导致裂纹的萌生和扩展.计算结果显示:在最初的10次热震循环中,涂层产生了垂直于界面的裂纹,在界面上没有出现裂纹,涂层与基体仍结合良好;在随后的热震循环中开始出现界面裂纹,界面裂纹开始于垂直裂纹的末端区域,当垂直裂纹与界面裂纹汇聚,会导致涂层剥离和涂层失效.“,”The thermal shock behavior of molybdenum disilicide (MoSi2)/molybdenum (Mo) coating and the crack propagation were evaluated by heating the coating to 1000 ℃,and then cooling it down to room temperature under the protection atmosphere of hydrogen during the thermal shock cycle.Meanwhile the thermal stress distribution of MoSi2/Mo coating during thermal shock was calculated by Abaqus software.The development process of crack during thermal shock cycles was discussed.The results show that there is a high thermal shock stress between the Mo substrate and MoSi2 coating,which can lead to the crack initiation and propagation.According to the extended finite element simulation results,the cracks appear perpendicular to the interface during the first ten thermal shock cycles,while the coating is still well bonded with the substrate and shows no signs of crack along the interface.The interracial crack appears in the subsequent thermal shock cycles.The interfacial crack begins at the end zone of the vertical crack.When the vertical crack and the interfacial crack converge,the coating peels off and the coating failure occurs.